A barcode (also bar code) is a machine-readable representation of information (usually dark ink on a light background to create high and low reflectance which is converted to 1s and 0s). Code 93 is a Barcode symbology designed in 1982 by Intermec to provide a higher density and data security enhancement to Code 39. A Data Matrix code is a two-dimensional matrix Barcode consisting of black and white square modules arranged in either a square or rectangular The term machine-readable (or computer-readable) refers to information Encoded in a form which can be read (i Originally, barcodes stored data in the widths and spacings of printed parallel lines, but today they also come in patterns of dots, concentric circles, and text codes hidden within images. Barcodes can be read by optical scanners called barcode readers or scanned from an image by special software. Historical precedent Scanners can be considered the successors of early telephotography input devices consisting of a rotating drum with a single Photodetector at A barcode reader (or barcode scanner) is an electronic device for reading printed Barcodes Like a Flatbed scanner, it consists of a light source a lens Barcodes are widely used to implement Auto ID Data Capture (AIDC) systems that improve the speed and accuracy of computer data entry. A computer is a Machine that manipulates data according to a list of instructions. An advantage over other methods of AIDC is that it is less expensive to implement. It will cost about US$0. 005 to implement a barcode compared to passive RFID which still costs about US$0. Radio-frequency identification ( RFID) is an automatic identification method relying on storing and remotely retrieving data using devices called RFID tags or 07 to US$0. 30 per tag. 
The first patent for a bar code type product (US Patent #2,612,994) was issued to inventors Joseph Woodland and Bernard Silver on October 7, 1952. Norman Joseph Woodland (born September 6, 1921) is best known as one of the inventors of the Barcode, for which he received US Patent 2612994 in October Its implementation was made possible through the work of Raymond Alexander and Frank Stietz, two engineers with Sylvania (who were also granted a patent), as a result of their work on a system to identify railroad cars. Sylvania Electric Products was a US manufacturer of diverse electrical equipment including at various times radio transceivers Vacuum tubes, semiconductors and mainframe It was not until 1966 that barcodes were put to commercial use and they were not commercially successful until the 1980s. 
While traditionally barcode encoding schemes represented only numbers, newer symbologies add new characters such as uppercase letters, or even the complete ASCII character set. American Standard Code for Information Interchange ( ASCII) The drive to encode more information in combination with the space requirements of simple barcodes led to the development of matrix codes (a type of 2D barcode), which do not consist of bars but rather a grid of square cells. Stacked barcodes are a compromise between true 2D barcodes and linear codes (also known as 1D barcodes), and are formed by taking a traditional linear symbology and placing it in an envelope that allows multiple rows.
Since their invention in the 20th century, barcodes — especially the UPC — have slowly become an essential part of modern civilization. The Universal Product Code ( UPC) is a barcode symbology (ie a specific type of Barcode) that is widely used in the United States and Their use is widespread, and the technology behind barcodes is constantly improving. Some modern applications of barcodes include:
The best-known and most widespread use of barcodes has been on consumer products. The Universal Product Code ( UPC) is a barcode symbology (ie a specific type of Barcode) that is widely used in the United States and The UPC symbol is a response to a business need first identified by the US grocery industry in the early 1970s.
Believing that automating the grocery checkout process could reduce labor costs, improve inventory control, speed up the process, and improve customer service, six industry associations, representing both product manufacturers and supermarkets, created an industry wide committee of industry leaders. Their two-year effort resulted in the announcement of the Universal Product Code and the U. P. C. barcode symbol on April 1, 1973. Events 527 - Byzantine Emperor Justin I names his nephew Justinian I as co-ruler and successor to the throne Year 1973 ( MCMLXXIII) was a Common year starting on Monday (link will display full calendar of the 1973 Gregorian calendar. The UPC Symbol that was chosen by the committee was a modified version of a symbol design that was submitted by IBM. International Business Machines Corporation abbreviated IBM and nicknamed "Big Blue", is a multinational Computer Technology IBM also designed five versions of the UPC symbology for future industry requirements — UPC A, B, C, D, and E.  The U. P. C. made its first commercial appearance at the Marsh Supermarket in Troy, Ohio in June 1974. Marsh Supermarkets is a retail food chain headquartered in Indianapolis, Indiana, with stores throughout Indiana and parts of Ohio 
Originally, the modern day bar code was developed to identify railroad cars. However, a toll bridge in New Jersey requested that a similar system be developed so that it could quickly scan for cars that had paid for a monthly pass. Then the U. S. Post Office requested that a similar system be developed so that it could keep track of which trucks had entered the yard and when. These applications required special retroreflective labels. Finally, KalKan dog food asked the Sylvania team to develop a simpler (and cheaper) version which they could put on cases of dog food for inventory control. This, in turn, led to the grocery industry's interest.
Economic studies conducted for the grocery industry committee projected over $40 million in savings to the industry from scanning by the mid-1970s. Those numbers were not achieved in that time frame and there were those who predicted the demise of barcode scanning. The usefulness of the barcode required the adoption of expensive scanners by a critical mass of retailers while manufacturers simultaneously adopted barcode labels. Neither wanted to move first and results weren't promising for the first couple of years, with Business Week proclaiming "The Supermarket Scanner That Failed. "
The mapping between messages and barcodes is called a symbology. The specification of a symbology includes the encoding of the single digits/characters of the message as well as the start and stop markers into bars and space, the size of the quiet zone required to be before and after the barcode as well as the computation of a checksum. A checksum is a form of Redundancy check, a simple way to protect the integrity of data by detecting errors in data that are sent through space ( Telecommunications
Linear symbologies can be classified mainly by two properties:
Some symbologies use interleaving. Interleaving in Computer science is a way to arrange Data in a non- Contiguous way in order to increase performance The first character is encoded using black bars of varying width. The second character is then encoded, by varying the width of the white spaces between these bars. Thus characters are encoded in pairs over the same section of the barcode. Interleaved 2 of 5 is an example of this. Interleaved 2 of 5 is a continuous two-width Barcode symbology encoding digits It is used commercially on 135 film and on cartons of products while the
Stacked symbologies consist of a given linear symbology repeated vertically in multiple.
There is a large variety of 2-D symbologies. The most common are matrix codes, which feature square or dot-shaped modules arranged on a grid pattern. 2-D symbologies also come in a variety of other visual formats. Aside from circular patterns, there are several 2-D symbologies which employ steganography by hiding an array of different-sized or -shaped modules within a user-specified image (for example, DataGlyphs). Steganography is the art and science of writing hidden messages in such a way that no one apart from the sender and intended recipient even realizes there is a hidden message
Linear symbologies are optimized to be read by a laser scanner, which sweeps a beam of light across the barcode in a straight line, reading a slice of the bar code light-dark patterns. In the 1990s development of CCD imagers to read bar codes was pioneered by Welch Allyn. Imaging does not require moving parts, like a laser scanner does. In 2007, linear imaging is surpassing laser scanning as the preferred scan engine for its performance and durability.
Stacked symbologies are also optimized for laser scanning, with the laser making multiple passes across the barcode.
2-D symbologies cannot be read by a laser as there is typically no sweep pattern that can encompass the entire symbol. They must be scanned by a camera capture device.
The earliest, and still the cheapest, barcode scanners are built from a fixed light and a single photosensor that is manually "scrubbed" across the barcode. A barcode reader (or barcode scanner) is an electronic device for reading printed Barcodes Like a Flatbed scanner, it consists of a light source a lens Photosensors or photodetectors are Sensors of Light or other Electromagnetic energy
Barcode verifiers are primarily used by businesses that print barcodes, but any trading partner in the supply chain could test barcode quality. It is important to "grade" a barcode to ensure that any scanner in the supply chain can read the barcode. Retailers levy large fines and penalties for non-compliant barcodes.
Barcode verifiers work in a way similar to a scanner but instead of simply decoding a barcode, a verifier performs a series of eight tests. Each test is given a grade from 0. 0 to 4. 0 (F to A) and the lowest of any of the tests is the scan grade. For most applications a 2. 5 (C) grade is the minimum acceptable grade.
Barcode Verifier Standards
Barcode Verifier Manufacturers (partial list)
Barcode Verifier Test Code Manufacturers ((traceable reflectance and linear measure) used to check proper function of verifiers)
In point-of-sale management, the use of barcodes can provide very detailed up-to-date information on key aspects of the business, enabling decisions to be made much more quickly and with more confidence. For example:
Besides sales and inventory tracking, barcodes are very useful in shipping/receiving/tracking.
The reason bar codes are business friendly is that bar code scanners are relatively low cost and extremely accurate – only about 1/100,000 entries will be wrong.
|Plessey||Continuous||Two||Catalogs, store shelves, inventory|
|U.P.C.||Continuous||Many||Worldwide retail, GS1 approved|
|Codabar||Discrete||Two||Old format used in libraries, blood banks, airbills|
|Code 25 – Non-interleaved 2 of 5||Continuous||Two||Industrial (NO)|
|Code 25 – Interleaved 2 of 5||Continuous||Two||Wholesale, Libraries (NO)|
|CPC Binary||Discrete||Two||Post office|
|EAN 2||Many||Addon code (Magazines), GS1 approved|
|EAN 5||Continuous||Many||Addon code (Books), GS1 approved|
|EAN 8, EAN 13||Continuous||Many||Worldwide retail, GS1 approved|
|GS1-128 (formerly known as UCC/EAN-128), incorrectly referenced as EAN 128 and UCC 128||Continuous||Many||Various, GS1 approved|
|GS1 DataBar formerly Reduced Space Symbology (RSS)||Continuous||Many||Various, GS1 approved|
|ITF-14||Continuous||Many||Non-retail packaging levels, GS1 approved|
|Latent image barcode||Neither||Tall/short||Color print film|
|PLANET||Continuous||Tall/short||United States Postal Service|
|POSTNET||Continuous||Tall/short||United States Postal Service|
|OneCode||Continuous||Tall/short||United States Postal Service, replaces POSTNET and PLANET symbols|
|MSI||Continuous||Two||Used for warehouse shelves and inventory|
|RM4SCC / KIX||Continuous||Tall/short||Royal Mail / Royal TPG Post|
|Telepen||Continuous||Two||Libraries, etc (UK)|
A matrix code, also known as a 2D barcode or simply a 2D code, is a two-dimensional way of representing information. It is similar to a linear (1-dimensional) barcode, but has more data representation capability.
|3-DI||Developed by Lynn Ltd.|
|ArrayTag||From ArrayTech Systems.|
|Aztec Code||Designed by Andrew Longacre at Welch Allyn (now Hand Held Products). Aztec Code is a 2 dimensional Matrix style Bar code symbology Public domain.|
|Small Aztec Code||Space-saving version of Aztec code.|
|bCODE||An SMS text code sent to mobile devices and read photographically.|
|Bullseye||The barcode tested in a Kroger store in Cincinnati. It used concentric bars.|
|Chromatic Alphabet||an artistic proposal; uses 26 different color hues. Hue is one of the main properties of a Color described with names such as " Red " " Yellow " etc |
|Chromocode||uses black, white, and 4 saturated colors. |
|Codablock||Stacked 1D barcodes.|
|Code 1||Public domain.|
|Code 16K||Based on 1D Code 128.|
|Code 49||Stacked 1D barcodes from Intermec Corp.|
|ColorCode||ColorZip developed colour barcodes that can be read by camera phones from TV screens; mainly used in Korea. |
|CP Code||From CP Tron, Inc.|
|d-touch||readable when printed on deformable gloves and stretched and distorted|
|DataGlyphs||From Palo Alto Research Center (also known as Xerox PARC). See http://www.dataglyphs.com for details.|
|Datamatrix||From RVSI Acuity CiMatrix/Siemens. A Data Matrix code is a two-dimensional matrix Barcode consisting of black and white square modules arranged in either a square or rectangular Believed to be public domain, but this status is being challenged. See Datamatrix#Patent Issues for details. A Data Matrix code is a two-dimensional matrix Barcode consisting of black and white square modules arranged in either a square or rectangular|
|Datastrip Code||From Datastrip, Inc.|
|Dot Code A||Designed for the unique identification of items.|
|EZcode||Designed for decoding by cameraphones. A EZcode is a matrix code (or two-dimensional Bar code) created by ETH Zurich and licensed by Scanbuy (www http://www.scanbuy.com|
|High Capacity Color Barcode||Developed by Microsoft; licensed by ISAN-IA. The High Capacity Color Barcode (HCCB is a new system of Barcodes developed by Microsoft. Microsoft Corporation is an American multinational Computer technology Corporation, which rose to dominate the Home computer For the band called ISAN see Isan (band International Standard Audiovisual Number ( ISAN) is a unique identifier for audiovisual works and related|
|HueCode||From Robot Design Associates. Uses greyscale or colour. |
|INTACTA. CODE||From INTACTA Technologies, Inc.|
|InterCode||From Iconlab, Inc. The standard 2D barcode in South Korea. All 3 South Korean mobile carriers put the scanner program of this code into their handsets to access mobile internet, as a default embedded program.|
|MaxiCode||Used by United Parcel Service. MaxiCode is a Public domain, machine readable symbol system originally created and used by United Parcel Service. United Parcel Service Inc ( commonly referred to as UPS, is one of the world's largest Package delivery companies Now Public Domain|
|mCode||Developed by Nextcode Corporation specifically for camera phone scanning applications. Designed to enable advanced cell mobile applications with standard camera phones.|
|MiniCode||From Omniplanar, Inc.|
|PDF417||Originated by Symbol Technologies Public Domain. PDF417 is a stacked linear Bar code symbol used in a variety of applications primarily Transport, Identification cards and Inventory management Symbol Technologies is a manufacturer and worldwide supplier of mobile data capture and delivery equipment The most common 2D barcode.|
|Micro PDF417||Facilitates codes too small to be used in PDF417.|
|PDMark||Developer by Ardaco.|
|PaperDisk||High density code — used both for data heavy applications (10K-1 MB) and camera phones (50+ bits). Developed and patented by Cobblestone Software|
|Optar||Developed by Twibright Labs and published as free software. Aims at maximum data storage density, for storing data on paper. 200kB per A4 page with laser printer.|
|QR Code||Developed, patented and owned by TOYOTA subsidiary Denso Wave initially for car parts management. A QR Code is a matrix code (or two-dimensional Bar code) created by Japanese corporation Denso-Wave in 1994 Now public domain. Can encode Japanese Kanji and Kana characters, music, images, URLs, emails. De-facto standard for Japanese cell phones.|
|Semacode||A Data Matrix code used to encode URLs for applications using cellular phones with cameras. Semacode is a software company based in Waterloo Ontario, Canada. Uniform Resource Locator is an URI which also specifies where the identified resource is available and the protocol for retrieving it A camera is a device used to capture images either as still Photographs or as sequences of moving images ( Movies or Videos.|
|SmartCode||From InfoImaging Technologies.|
|Snowflake Code||From Marconi Data Systems, Inc.|
|ShotCode||Circular barcodes for camera phones by OP3. ShotCode is a circular Barcode created by High Energy Magic of Cambridge University. A camera phone is a Mobile phone which is able to capture either still Photographs or Motion video. Originally from High Energy Magic Ltd in name Spotcode. Before that probably known as TRIPCode.|
|Trillcode||From Lark Computers. Designed to work with mobile devices camera or webcam PC. Can encode a variety of "actions".|
|UltraCode||Black-and-white & colour versions. Public domain. Invented by Jeffrey Kaufman and Clive Hohberger.|
|UnisCode||also called "Beijing U Code"; a colour 2D barcode developed by Chinese company UNIS|
|VeriCode, VSCode||From Veritec, Inc.|
|WaterCode||High-density 2D Barcode(440 Bytes/cm2) From MarkAny Inc.|